Process for producing styrol and its homologues from aromatic hydrocarbons



June 9, 1925. 1,541,175

OSTROMISLENSKY ET AL PROCESS FOR PRODUCING STYROL AND ITS HOMOLOGUESFROM AROMATIC HYDROCARBONS f Filed May 7 1924 Hurwe hm/gfx Patented June9, i925.

UNITED STATESPATENT OFFICE.

IWAN OSTBOMISLENSKY AND MORRIS G. SHEPABD, OF NEW YORK, N. Y., ASSIGNOBBTO THE NAUGATUCK CHEMICAL COMPANY, OF NAUGATUCK, CONNECTICUT, A

CORPORATION OF CONNECTICUT.

PROCESS FOB PRODUCING STYROL AND ITS HOMOLOGUES FROM AROMATIC HYDRO-CARBONS.

Application led May 7,

To all whom z't may concern:

Be it known that we, .IWAN Os'rnoMis- LENsKY and Monni's G. SHEPARD, acitizen of Russia and a citizen of the United States, respectively, bothresidents of New York, county and State f New York, have inventedcertain new .and useful Im rovements in Processes for Producing tyroland its Homologues from Aromatic Hydrocarbons, 'of which the followingis a full, clear, and exact description.

This invention relates to the production of styi'ol and its homologuesfrom hydrocarbons havin eight or more carbon atoms. such as ethyl enzol,xylol, homoloues and analogues thereof, by pyrogenic ecomposition. s l

The objects of the present invention are to provide a process of thekind describedV `which shall produce a high yield of styrol, and itshomologues, which shall be economical and can be carried out in apractical way with simple apparatus.

The invention accordingly consists, of a f process for making styroland/or its homoogues which 'comprises heating a hydrocarbon having atleast eight carbon atoms and at least 10 hydrogen atoms to a tem-lperature of approximately 450 C. to approximately 700 C., and partiallydecom-l posing,r the hydrocarbon to form a compound havin the generalformula ALCH: CH, where r. is aryl.

This case is a continuation in part of our 'application Serial No.`648,751, tiled June In carrying out the invention the apparatus showndiagrammatically in the figure may be ein loyed. It comprises a sourcelof ,carbon dioxide or other neutral gas. led `in by a Pipe 1 through atlowmeter 2 by means o pipe 3 into the interior of an iron pipe 4 whichisl heated in any desired manne!` to the re uired temperature, as by gasburners 5. Jommunicatinfv also. with this tube 4 through a valve 6 andsight glass 7 is a container 8 for the hydrocarbon. The temperatureisdetermined by means of a thermocouple 9 arranged kin the presentembodiment to record through the indicator 10 the temperature of the gasin the interior of the tube at the \middle. Electric or other heatingmeans may be employed if desired. The tube 4 leads into the Liebigcondenser 1921. Serial Fc. 711,583.

vcharged 4at 16. The manometer 17 acts simultaneously as a pressuregauge and safety device. The baiiies 18 are used to insure that thefluid `is uniformly heated.

The processes for producing styrol, its homologues and analogues may bedivided into two grou s, which are designated as follows: (1)ehydrogenation' of ethylbenzene or its homolo es at high temperatures(450-700 0.); an (2) splitting oi hydrocarbons from various homologuesor analogues of benzol which have more than two gtomscof carbon in aside chain at 500- 1. Dehydrogenation of ethyl benzol.

and/or its homologues at high temperatures The general formula for thereaction here occurring is Ar.CH,.CH :Hd-ALCH CIL, where Ar. is aryl.

Under this group comes the treatment of ethyl benzol, the procedure fortreatment of which is as follows: Eth l benzol is run from container 8into the interior of iron tube 4 at a measured rate.4 The a paratushaving been previously cleared o air. by passin a stream of carbondioxide or other neutra gas from the pipe 1 therethrough and the irontube having been heated up to approximately 650 C. as shown bytheindicator 10, this temperature is maintained throu hout the run withinplus or minus 15 The rate of iow of ethyl benzol is maintained atapproximatel 15 to 20 gm s./ min. and the rate of ow o carbon dioxide asindicated by the ilowmeter 2 at 50to 60 c. c./mn., the pressure .in theheating chamber 4 being atmosheric. or these conditions of tem ofiiowshould be 2 in. an

rature and th total l ap roximatel The internal diameter ofv the tab: n

of the heated portion (that withinthe nace is 54 in. The total internal.volume of the reacting portion of the tube is thereforef170 cu. in. inroundnumbera The process is continuous, lt'being 'only uw sary tointerrupt for repairs, etc. The Areaction which takes place upon passageof the ethyl enzol through the heated tube is as follows:

Other reactions may take place and do take place to produce gas, carbonand tarrv products. The styrol and tarry products are collected togetherin the container-13 while the gases pass to the gas holder 14. A processfor separating the styrol from the tarry products is set forth in ourcopending a plication Serial No. 711,584, filed May i; 1924. Thisprocess comprises distilling the mixture with steam, separating thedistillate from water and drying it. The dried roduct is placed in anautoclave and heate ap roximately for 16 hours at ,180 C.-200Polymerization of styrol to form metastyrol occurs. An accelerator ofpolymerization maybe employed, if desired. With benzoyl peroxi e as anaccelerator polymerization may be accomplished in approximately 8--12Ihrs. at 180 C. After polymerization the autoclave is opened and itscontents subjected to a tractional distillation, the final residueremaining above 145 C. representing metastyrol. Under the conditionsofpressure and temperature and using an iron tube as indicated, theamount of styrol produced from a thousand gms. of ethyl benzol isapproximately 250 gms. This quantity of roduct represents an eicieney ofapproximately 32%.

The term elliciency as used, means the per cent of the theoretic yieldof styrol calculated on the basis of the actual ethyl benzol consumed inthe process. In carrying out the above process, 220 gms. of ethyl benzolwas recovered per 1,000 gms, of ethyl benzol used, which means that 780gms. of ethyl benzol were consumed. The etliciency therefore ona'percentage basis is -250X100-:-780 or 32%. This calculation neglectsthe slight dilerence in the molecular weight of ethyl benzol (106) andstyrol Instead of ethyl benzol which has the formula. GSH, the isomerxylol which also has the formula GSH, may be employed undersubstantially the same conditions as those indicated above for ethylbenzol. The reaction may be expressed as CH4 (C1102: C,II,CH:CH2+H,. Theamount of styrol produced from 1000 grams of xvlol is approximately 50grams and the eliiciency approximately 20%.

The conditions given in the preferred embodiment above, have been variedin order to determine among other things, the optimum temperature forvarious tube materials. the optimum rate of flow of ethyl benzol and thevalue of the use of a neutral gas to promote the How of ethyl benzolthrough the heating tube.

An iron tube, due to the ease with which such tubes may be procured, hasbeen indicated in the preferred embodiment above but numerous tests onother tubes show that iron may be replaced if desired. For example,quartz or copper tubing may be used in which case results quite similarto those with the iron tube are obtained. An exception is that ofnickel. When nickel gauze was placed in an iron tube the results werenot as satisfactory, the tendency being to form large quantities of gasand carbon at the expenseof the desired product, styrol. The optimumrate of flow established will vary with variation of other factors ofthe apparatus and process, for instance, variations in the shape of theheating chamber and the distribution of heat in this chamber wouldinfluence the rate of flow and variations of pressure within thechamber.` would also influence the rate of flow. There is apparently arelationship of the volume in which V is the volume of the heatedportion ofthe tube in cubic centimeters, R the rate of llow of ethylbenzol into the tube in grams per minute; T the temperature of theinterior of tube at the middle point in degrees centigrade; and K theparameter varying betweenthe values .8 and 1.2, the oitlmum efliciencybeing secured when I :1. The optimum elliciency is about. 36%. Thisequation holds for all practicable rates of flow and all practicablesizes of tubes.

In order to determine the effect of the carbon dioxide or other neutralgas employed, a run was made using the iron tube as in the preferredembodiment in which no neutral gas was employed and it was found thatthe results were quite similar to those obtained when the neutral gaswas used. However, the operation of the apparatus is simplified by theuse of this nelltral gas as the regulation of the rate of flow of ethylbenzol is thereby facilitated.

Tf any unchanged ethyl benzol or xylol is collected, this material mayagain be run through the apparatus to produce st vrol with an efficiencysubstantially the same as given b v the original ethyl benzol or xylol.

Other gases such as nitrogen and steam may be used to replace carbondioxide the gas promoting How through the heat ingr chamber. The processmay be run con llo ' may be carried out as follows:

tinuously. It requires little attention and is relatively economical.

In addition to ethyl benzol and xylol mentioned above, variousothermaterials hav been similarly treated' falling within the presentgroup. The products obtained an l the raw materials are as follows: (a)orthomethyl styrol from orthomethyl ethyl benzol, (b) para meth l styrolfrom para methyl ethyl benzol, {c} symmetrical dimethyl styrol from 1.3. 5. dimethyl ethyl benzol, and (d) ethyl styrol from diethyl benzol.

The starting points for (a) and b) may be obtained b ethylating toluol.ymmetrical dimethy styrol may be obtained by similar ethylization ofxylol. The following is a tabulation of results obtained in thedehydrogenation of the isomer xylol and homologues of ethyl benzol intothose of ,styrol followin a 's1milar processto that set forth for dehyrogenation of ethyl benzol.

A Boilingtem- 140 176-185 145-100 16o-165 130 peratureof original|(nci)xture B Nature of xy1ol- 1.3.5 di- Ortho- Parme Diethylactivehymethyl methylthylbenzol1 drocarbon. ethylethylethylbenzol benlolbenzol C Amount in lgms. 0.62 gms. 0.5lgms. 0.52gms. lsgms.

grams per minute. D Durationoi l hr. 7 6h. 45m. 3h. 15m. 7hrs. 47 mins.

lprocesa rn s. E ixture 1000gms-250gms. 109gms. 217m. 849 gms.

subjected to pyroization ngms. F Tempera- 650 6to-650 6804520 G40-650650 tureofiun nace (C). G Liq uid 944mm. 225gms. 97gms. lgms. 800 gms.

products obtained. HDryHydro- 833m. 178gms. sgms. l'gms. B84gms .carbonsdistilled w l t h steam. lNature o1 Meta- Ortho- Parame- E th product.meta methyl t h yl styro .1 styrol obdimestyro. styrol. tamed. t h y lstyrol. .I Content oi 5.7% 31.7% 28.6% 35.7% 23.8%

styrol or .Mm f'.-

081108 Il distillate '(steem) by analysis Whether the process is carriedout in iron or quartz tubesthe results are substantially as given above.Actually the above results were gotten using an iron tube for xylol andgrou l as follows: Ar.C,H,R=RHl-Ar. H:

a quartz tube for the other substances. The quartz tube had thefollowing dimensions: 1" diameter by 27 long. It has been found that therelationship of the volume in the heating chamber, the rate of flow andtemperature exists in a similar Way for products other than ethyl benzolwhich may be expressed mathematically by the formula given in connectionwith the process employing ethyl benzol.

nstead of using ethyl benzol or its homologues separately, mixtures ofethyl benzol and/or of its homologues may be passed through a heatedtube and a solution containing styrol and its homologues or thehomologues alone obtained. For this purose the mixtures of ethyl benzoland its omologues may conveniently be obtained by eth latin mixturescontaining benzol, toluol an xylo as for example the fractions obtainedfrom coal tar, gas tar, etc. boiling from 80 to 130 C.

Ethyl benzol, xylol, etc. containing styrol in solution may also be usedas raw material, for example, ethyl benzol which has already beensubjected to the pyro en'ization action of the hot tube. Such ethybenzol or xylol, etc. containin through the tuge. he result of suchaction is to enrich or increase the concentration of styrol.

For example, if a solution containing around 14% of styrol in eth lbenzol is passed through the hot tube un er the usual conditions as setforth in our application Serial No. 648,751, filed Junev30, 1923, theresulting raw product would contain around styrol, whereas ordinarilyusing pure ethyl benzol the styrol content would run around 20%. Theethylbenzol recoverable from this raw product is essentially in the sameproportion as that from pure ethyl 2. Splitting oil' hydrocarbons fromvarious homologues or analogues of benzol which have more than two atomsof carbon in the side chain at G-700 C.

The reaction involved in this I Iis 2, where Ar. is aryl and R reresents an alkyl radical. This process has een investigated inconnection with the treatment of cymene.

In carrying out the process with cymene the following reaction occurs:

Specifically the process emploing cymene ymene is introduced fromcontainer, 8 into the tube 4 of quartz at a rate of .5-.6 ams perminute. The tube is heated to 650 C., the diameter of the tube being 25cm. and length subjected to heating 67 cm. A current of carbon dioxideat low pressure is passed from pipe 1 through the tubecontinuouslyduring the st rol may be repassed' whole process. The liquid reactionproducts l condense in the receiver 13 which 1s water cooled. Themethane formed in the reaction may be collected in the gasometer 14. Theproduct resulting from treatment of cymene methyl styrol appeared in thedistillate and the remaining grams of liquid products in the distillinglask. An analysis of the distillate showed that it contained grams, i.e. 53.2% of paramethylstyrol, the

i main part of the by-products in this crude ticular it may be obtainedfrom cheap varieties of turpentine which in turn are made by distillingshavings of pine-tree stumps with steam.

The processes described are simple and economical, and require simpleapparatus only. They produce a relatively high yield of the desiredproduct.

It will thus be seen that among others the objects of the inventionabove enumerated are. achieved.

As many apparently widely dili'erent embodiments of this invention maybe made without departing from the spirit thereof, it will be understoodthat We do not intend to limit ourselves to the specific embodimentherein set forth except as indicated in the appended claims.

Having thus described our invention, what we claim and desii'e toprotect by Letters Patent is:

1. A process for ina-king compounds of the type ArCI-I: CH2 where Arrepresents aryl, which comprises heating a hydrocarbon having thegeneral foi-mula ArCJLR where R represents a monovalent substitution toa temperature of approximately 450700 C.

(ill

Aand partially decomposing the hydrocarbon to forni ArCH: CH2. A

2. A process for making compounds of the type ArCHzCH2 where Arrepresents` changed .\i'C,lLR, and the ArCH: CH2 therefrom. y

4. A process for making compounds of the type ArCH:CH2 where Arrepresents aryl which com )rises passing a stream of an aromaticliydrocarbon having the formula ArCJLR where R represents an elementthrough a conduit heated to appmximately 450-T00, and decomposing Sie*(zlLR portion thereof to yield A rCII:

5. A process for making compounds oi the type ArHzCH2 where Arrepresents aryl, which comprises heating a hydrocarbon having thegeneral formula ArC,H,R where Ar represents aryl and R representshydrogen, approximately to 4-50-'700J C., and splitting ott' hydrogentherefrom to form ArCH: CH2.

A process t'or making compounds of the type ArHzCH2 where Ar representsaryl, which comprises heating a hydrocarbon having at least eight carbonatoms and at least ten hydrogen atoms to a temperature of 450 (lf-700oC. approximately, and partially decomposing the hydrocarbon to form ArCHCH2.

7. A process for making ArCHzCH3 where Ar represents aryl whichcomprises passing a stream of a vaporized aromatic hydrocarbon having atleast eight carbon atoms and at least ten hydrogen atoms through aconduit heated to a temperature of approximately 700 at a rate of 'lowof hydrocarbon and with a. volume of conduit such that K falls withinthe limits of .t3-1.2 in the formula v .064 V/R -l-T 633 where V vis thevolume of the heated portion of the tube in cubic centimeters, lt therate of flow of material into the tube in grains per minuta T thetemperature of the interior of the tube at the lniddle point in degreescentigrade, and K thc parameter derived therefrom.

8. A process for making ArCH CH2 where Ar represents aryl whichcomprises heating ahydrocarbon having the general formula ArCHzCl-l, toa temperature ot' approximately -1-50O (1 -700 C., and ipartiallydecomposing the hydrocarbon lo forni a coniporirind having the generalformula ArCl-I 0. A processl for making ArCH: CHJ where Ar representsaryl -which comprises passing a stream of an aromatic hydrocarbon havingthe formula UCI-12CH, through a conduit heated to a temperature ofapproximately 450 to a proximately "1'00J C. and splitting off hy rogentherefrom to form a compound having the formula ArCH: CH2.

10. A process for making ArCI-LCH,

recovering where Ar represents aryl which comprises passing a stream` ofan aromatic Ihlydro- 4carbon having the formula ArC ZCH,

through a conduit heated to a temperature of approximately 450 C.toapproximatel'y 700 C., collecting a mixture containing a substancehavin" the formula ArCH CH2, tarry matter and unchangedArCH2CH3, andrecovering the substance ArCH: CH2 therefrom.

11. A process for making styrol which comprises passing a stream of anaromatic hydrocarbon having the formula CsHm through a conduit heated toa temperature of approximately 450 C. to approximately 700 C. andliberating hydrogen from the aromatic hydrocarbon to form styrol.

12. hprocesserfor making :any1-o1 which comprises passing a stream ofethyl benzol through a conduit heated to a temperature of approximately450"- C. to approximately 700 C., and splitting off hydrogen from the'ethyl benzol to form styrol.

where V is the volume of the heated'portion of the tube in cubiccentimeters, R the rate of How of material into the tube in grams perminute, T the temperature of the interior of the tube-at the middlepoint in degrees centigrade, and -K the parameter detherefrom.

Signed at New York, New York, this 30 day of April, 1924.

IWAN osTRoMIsLENsKY. Mouais G. SHEPARD.

carbon aromatic hydrocarbon to forni styrol.

12. .k .processfor making -styi'ol .which comprises passing a stream ofethyl benzol through a conduit heated to a temperature of approximately450f C. to approximately 700 C., and splitting ofl' hydrogen from theethyl beiizol to form st vrol.

13. process for making styrol which comprises passing a stream ofvaporized ethyl benzol through a conduit heated to a temperature ofapproximately 700 C: at a rate of How of hydrocarbon and with a volumeof conduit such that K falls within the limits .S4-1.2 in the formula.064 V/R+T where V is the volume of the heated portion of the tube incubic centimeters, R the rate of flow of material into the tube ingrams` per minute, T the temperature of the interior of the tiibeat theliiiddlc point in degrees centigrade, and K the parameter dcriT'edtherefrom.

Signed at New York, New York, this 30 day of April, 1924.

IWAN OSTROMISLENSKY. MORRIS G. SHEPARD.

Certificate of Correction.

, It is hereby certified that in Letters Patent No. 1.541,17 5,

anted June 9, 1925,

upon the application of Iwan Ostroinislensky and Morris G. S epard, ofNew York 1*.. Y., for an im rovement in Processes for Producing Styroland its Homologues from Aromatic ydrocarbons, an error appears in therinted s ilication requiring correction as follows: Page 3, in the hrstcolumn o the tab e under the letter heading I, strike out the word strol and insert the saine in the second column of the table opposite thesame heat ing I formulae and insert instead saine page, line 108, strikeout the and that the said Letters Patent should be read with thiscorrection therein that tliewsa'me may conform to the record of the casein the Patent Office.

bigned andsealed this 22d day of June, A. D. 1926.

[sinn] M. J. MOORE, Acting (lommzsaioner of Patents.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,541,175, grantedJune 9, 1925, upon the application of Iwan Ustromislensky and Morris G.Shepard, of New York, N. Y., for an im rovement in Processes forProducing Styrol and its Homologues from Aromatic ydrocarbons, an errorappears in the printed s cifcation requiring correction as follows: Page3, in the hrs-st column of the tab e, under the letter heading I, strikeout the word st ro and insert the suine in the second column of thetable o posite the same hea( ing I same page, line 108, strike out theformula: and insert instead and that the said Letters Patent should beread with this correction therein that the same may conform to therecord of the case in the Patent Oice.

Signed and sealed this 22d day of June, A. D. 1926.

[SEAL] M. J. MOORE,

Acting ('ommsm'oner of Patents.

